Shooting head filling device

ABSTRACT

The device comprises a filling assembly (6) with a storage hopper (3) for molding material (2), an outlet member (4) for discharging the molding material (2) into the shooting head (1), and a gate (5) for closing the outlet member (4), the filling assembly (6) being mounted for vertical movement on a machine frame (7) for purposes of immersing the outlet member (4) into the shooting head (1) that is to be filled. To ensure that, on the one hand, the filling assembly (6) is filled with the molding material (2) in an accurately predeterminable and reproducible manner and that, on the other hand, the filling level of the filling assembly (6) is accurately determined, the device is designed and constructed such that a weighing device (8) for determining the weight of the filling assembly (6) is arranged between the filling assembly (6) and the machine frame (7).

BACKGROUND OF THE INVENTION

The invention relates to a device for filling shooting heads withmolding materials, the device being provided with a filling assemblythat comprises a storage hopper for the molding material, an outletmember for discharging the molding material into the shooting head, anda gate for closing the outlet member, the filling assembly being mountedon a machine frame for vertical movement so as to immerse the outletmember into the shooting head to be filled.

In the foundry practice, core shooting machines have been known for manyyears. For casting molded products, the foundry cores or molds are madein most cases as separate parts. They are combined and joined to eachother to form a casting mold. An essential component of the coreshooting machines are the so-called shooting heads with shooting platesaccommodating the shooting nozzles. Molding sand, in particular coresand, i.e., a quartz sand previously compounded or coated with bindingagents is supplied to the shooting heads under discussion, from which itis blown or shot under a very high air pressure into the respectivemolds through the nozzles arranged in the shooting plate.

DE 41 28 952 C1 discloses a known device for filling shooting heads withmolding materials. However, this device is extremely problematic withrespect to monitoring its filling level. The filling level of the knowndevice, in particular in the region of the storage hopper is determinedby means of measuring probes, which project from the outside into thestorage hopper or terminate flush with the inside wall of the storagehopper, these measuring probes being provided at different heights fordetermining defined filling levels. However, on their measuring side,i.e., toward the interior of the storage hopper, these filling levelprobes have at least small steps or discontinuous transitions in theirwall and, thus, form critical regions, to which the nonflowable or moistmolding material may stick or adhere. In the course of several fillings,encrusted buildups form thereon, which are detected by the measuringprobe as the filling level or the molding material. Consequently, thearrangement of the measuring probes under discussion involves asystem-inherent imperfection to the extent that the measuring probeitself constitutes a cause for an erroneous measuring situationsimulating a filling level as a result of material accumulations in theregion of the measuring probe.

It is therefore the object of the present invention to improve andfurther develop a device for filling shooting heads of the kind underdiscussion, so that it is possible to determine with simple means thefilling level of the storage hopper, or to exactly predetermine and evenreproduce a filling of the filling assembly.

SUMMARY OF THE INVENTION

The device of the present invention for filling shooting heads achievesthe foregoing object by the provision of a weighing device which isconnected between the filling assembly and the machine frame, and sothat the weighing device determines the weight of the entire fillingassembly.

In accordance with the invention, the longstanding, proven method ofdetermining the filling level by means of measuring probes has beendiscarded. Instead, it has been recognized that the filling level of thefilling assembly or the storage hopper may be determined withoutadversely affecting the storage hopper, in that the entire fillingassembly is weighed. Within the scope of a simplest configuration of thedevice in accordance of the invention, it would be possible to determinethe net weight of the filling assembly before starting a first filling,and after determining accordingly the weight of the loaded fillingassembly, the previously determined net weight would have to be deductedfrom the gross weight. With a known pouring density of the moldingmaterials, the pouring volume could be calculated, if necessary, withthe quantity of forming material required for shooting cores beingeasily definable by also indicating the weight.

Further, it will be advantageous, when the weighing device is adjustedor zeroed to the net weight of the entire filling assembly, so that theweight of the molding material being in the filling assembly may bedetermined directly by means of the weighing device. The adjustment tozero that is to be performed with respect to the filling assembly, wouldhave the great advantage that a corresponding display indicatesexclusively the weight corresponding to the loaded molding material. Inthis connection, it would likewise be possible--on the basis of thepouring density of the molding material and its filling-dependentvolume--to directly indicate the direct correlation to the filling levelafter a preparation by a processor. A loading of the filling assemblycould be controlled via thus-acquired data. Likewise in this instance,it would be necessary to take into account the quantity of moldingmaterial required for filling a shooting head as well as the number ofthe shooting heads to be filled with the contents, namely a load, of thefilling assembly.

With respect to construction, the weighing device could be connected tothe filling assembly and operate between the filling assembly and themachine frame. Additional guideways or further hinges between thefilling device and the machine frame are advantageous for reasons ofstability, it being necessary in this instance to ensure only that theweight of the filling assembly is in fact operative on the weighingdevice. Likewise, the weighing device could be connected to the machineframe, and operate between the machine frame and the filling assembly.With respect to hinging the weighing device, it is to be ensured onlythat same is operatively connected, on the one hand, with the fillingassembly or a holder thereof and, on the other hand, with the machineframe or a corresponding holder thereof, and so that the mass of thefilling assembly is operative on the weighing device unimpeded orwithout external influences.

With respect to a particularly ingenious arrangement of the weighingdevice it will be advantageous, when the weighing device is associatedwith a lifting mechanism that is connected to the machine frame or tothe filling assembly and operates between the machine frame and thefilling assembly. This lifting mechanism causes the filling assembly tomove vertically for purposes of immersing its outlet member into theshooting head. More specifically, the lifting mechanism could comprise acylinder-piston arrangement serving as a drive. In this connection, aweighing cell serving to bias the weighing device could form again anintegral part of the cylinder-piston arrangement. Thus, the forceapplied could be measured, for example, via force gauges, on which themass of the filling assembly is operative directly or indirectly, forexample, even via a hydraulic pressure medium.

There exist various possibilities of perfecting and further developingthe teaching of the present invention in advantageous manner. To thisend, reference may be made to the following description of an embodimentof the invention with reference to the drawing. In conjunction with thepreferred embodiment of the invention with reference to the drawing,also generally preferred embodiments and further developments of theteaching are described.

BRIEF DESCRIPTION OF THE DRAWING

The single drawing figure is a schematic side view of the device inaccordance with the invention for filling shooting heads with a weighingdevice for determining the weight of the filling assembly.

The drawing illustrates schematically a device for filling a shootinghead 1 with molding materials 2, the device comprising a fillingassembly 6 with a storage hopper 3 for molding materials 2, an outletmember 4 for discharging the molding materials 2 into the shooting head1, and a gate 5 for closing the outlet member 4, the filling assembly 6being mounted for vertical movement on a machine frame 7 for purposes ofimmersing the outlet member 4 into the shooting head 1 that is to befilled.

In accordance with the invention, a weighing device 8 for determiningthe entire weight of the filling assembly is arranged between thefilling assembly 6 and the machine frame 7. Essential in thisarrangement is that the weighing device 8 is adjusted or zeroed to thenet weight of the filling assembly 6, so that the weight of the moldingmaterial 2 contained in the filling assembly 6 can be determined bymeans of the weighing device, which is only schematically illustrated inthe drawing.

As likewise shown in the drawing, the weighing device 8 is connected, onthe one hand, to the filling assembly 6 or to a holder 9 arrangedthereon and, on the other hand, to a lifting mechanism 10 operatingbetween the machine frame 7 and the filling assembly 6, and it is thusoperative between the filling assembly 6 and the machine frame 7. Asillustrated, the lifting mechanism 10 comprises a cylinder 11 and piston12, and the weighing device 8 comprises a weighing cell connected to thepiston 12. However, it is likewise possible to integrate the weighingdevice 8 in the lifting mechanism 10. In this instance, the weight canbe determined with reference to an increased pressure that develops inthe cylinder-piston arrangement as a result of the mass of fillingassembly 6.

Finally, it should be explicitly noted that the teaching claimed in thepresent invention relates basically to the determination of the fillinglevel of a device for filling shooting heads, namely on the basis ofdetermining the weight of the filling assembly. Any other developmentsof the teaching are possible, without being limited to the foregoingembodiment that has been described only by way of example.

We claim:
 1. A device for filling shooting heads with molding materialcomprisinga filling assembly comprising a shortage hopper for moldingmaterial, an outlet member connected to the storage hopper fordischarging the molding material into a shooting head, and a gate forselectively closing the outlet member, means mounting the fillingassembly for vertical movement on a machine frame for the purpose ofimmersing the outlet member into the shooting head, said mounting meansincluding a lifting mechanism fixed between the filling assembly and themachine frame and which comprises a cylinder-piston arrangement, and aweighing device connected between the filling assembly and the machineframe for determining the weight of the filling assembly, said weighingdevice comprising a weighing cell connected to the cylinder-pistonarrangement.
 2. The device as defined in claim 1 wherein the weighingdevice is zeroed to the net weight of the filling assembly so that theweight of the molding material contained in the filling assembly isdetermined by the weighing device.